A ceramic electrostatic chuck is fabricated by embedding an electrode between ceramic base materials of alumina or the like followed by sintering. By application of electrostatic clamping force to the incorporated electrode, the electrostatic chuck clamps a substrate such as a silicon wafer by electrostatic force. This type of electrostatic chuck has been put to practical use in the following configurations in order to supply electrostatic clamping force to the internal electrode. For instance, part of the conductor in electrical continuity with the electrode is exposed at the surface on the side opposite from the electrostatic clamping surface of the ceramic base material. Alternatively, a connector for power supply is joined to the electrode.
Patent Literature 1 discloses a structure of an electrostatic chuck including a connecting part (via) in electrical continuity with the internal electrode. In the electrostatic chuck described in Patent Literature 1, a conductive layer and an insulating film are sequentially laminated on a ceramic green sheet to form a laminated body. The laminated body is sintered to form a via in electrical continuity with the conductive layer (electrode).
However, the connecting part (via) having a smaller outer diameter is more susceptible to sintering shrinkage when sintering the ceramic. This tends to cause delamination of the metal material between the internal electrode of the ceramic base material and the connecting part (via). Furthermore, when sintering the ceramic, the metal material composing the connecting member may migrate in the ceramic base material to form a void due to surface tension of the metal material, or the electrode may be broken due to the thermal expansion difference between ceramic and metal. In particular, miniaturization of the outer diameter of the connecting member aggravates such problems and causes the problem of the decrease in reliability of the electrostatic chuck.